This study will use proactive risk assessment methods to identify hazards and model their risk in the primary care of elderly patients. We have chosen to focus on identifying hazards in the primary care of elderly ambulatory patients for three main reasons. First, primary care is the hub of healthcare delivery. This unique role leads to tremendous complexity that is greatly underappreciated. This complexity makes primary care likely to have a high prevalence of safety hazards. Second, the research team of safety engineers and primary care physicians from the University of Wisconsin-Madison Department of Family Medicine-Wisconsin Research and Education Network (WREN is the AHRQ-funded PRBN in Wisconsin) already has a long history of successful collaboration studying primary care patient safety that has resulted in five primary care patient safety studies and numerous publications on primary care patient safety. The PI and Co-Pi have [unreadable] co-published a book chapter on patient safety hazards in primary care. As such the research team brings together diverse expertise and a proven track record studying primary care patient safety. Third, the elderly are a vulnerable group at greater risk of being injured as a result of safety hazards. For example, the elderly are more susceptible to adverse drug events. The three Specific Aims we target are to (1) identify hazards the primary care of elderly patients, (2) conduct a proactive risk assessment of the identified hazards, and (3) compile a report detailing the documented hazards, the proactive assessment results and suggested approaches for eliminating identified hazards. The methods used to achieve Aims 1 and 2 will be rigorous proactive work system analyses followed by three proactive risk analysis methods: Variance Analysis, Hazard and Operability (HAZOP) studies, and Failure Mode and Effects Analysis (FMEA) led by PhD safety and human factors engineers collaborating with primary care clinicians. The methods are fully justified in the narrative text and compared and contrasted with other possible methods. Aim 3 will be guided by collaborations between safety experts and clinicians using evidence-based human factors engineering design guidelines. This study is significant because it addresses primary care patient safety among the elderly. The approach is well matched to the Aims. The innovativeness lies in the collaboration between recognized experts in safety engineering and primary care. The investigators have a history of successful collaboration and deliverables in primary care patient safety. [unreadable] [unreadable] [unreadable]